Characteristics of type 2 asthma phenotypes and oral corticosteroid (OCS) use in the International Severe Asthma Registry (ISAR) (STAR)

Study type

• Study type:
  Non-interventional study
• Scope of the study:
  Disease epidemiology

Non-interventional study

• Non-interventional study design:
  Cross-sectional

Study drug and medical condition

• Medical condition to be studied:
  Asthma

Population studied

• Age groups:
  Adults (18 to < 46 years)

  Adults (46 to < 65 years)

  Adults (65 to < 75 years)

  Adults (75 to < 85 years)

  Adults (85 years and over)
• Estimated number of subjects:
  3404

Study design details

• Main study objective:
  The main objective is to describe patients aged 18 years or older with GINA 4/5 asthma, enrolled in ISAR, by OCS use and biomarker distribution, Type 2 characteristics and individual biomarkers, prior to biologic initiation. An added objective is to describe those patients with low eosinophilic phenotypes and who have long-term OCS use prior to biologic initiation.
• Outcomes:
  Demographic and clinical characteristics will be described for GINA Steps 4/5 patients with no, intermittent and long-term OCS use. The prevalence of type 2 characteristics, as defined by biomarkers or concomitant type 2 disease, will also be presented. Demographic and clinical characteristics will be described for GINA Steps 4/5 patients with low eosinophilic phenotypes (blood eosinophils <150 cells/microL) and long-term OCS use.
• Data analysis plan:
  The final sample size will depend on the number of individuals with available data on biomarkers, OCS use and type 2 comorbidities. Analysis will be undertaken in STATA and R. As the study requires descriptive analyses, no inferential statistics will be performed. Continuous variables will be summarised using means, standard deviations, medians and interquartile ranges. Categorical variables will be shown as number and percentage.